The present invention relates to an apparatus for hemo(dia)filtration.
Specifically, though not exclusively, the invention can be usefully applied for realising a disposable fluid circuit associable to a machine for on-line preparation of a dialysis fluid with the aim of performing a hemo(dia)filtration treatment.
As is known, a hemo(dia)filtration treatment comprises stages of creating an extracorporeal circulation of a patient's blood, of passing the extracorporeal blood internally of a hemo(dia)filter having a semipermeable membrane, of ultrafiltering a part of the plasmatic liquid contained in the extracorporeal blood through the semipermeable membrane, and of introducing a replacement fluid into the extracorporeal blood before (pre-dilution) and after (post-dilution) the hemo(dia)filter. The quantity of replacement fluid introduced is equal to the quantity of ultrafiltered plasmatic liquid, minus the desired weight loss of the patient.
In particular the present invention relates to an apparatus comprising an extracorporeal blood circuit having an arterial line (which takes the extracorporeal blood from the patient to the hemo(dia)filter) and a venous line (which returns the blood from the hemo(dia)filter to the patient), a replacement liquid supply line for the extracorporeal blood circuit, a bifurcation dividing a main line of the supply line into a pre-dilution line connected fluidly to the arterial line and a post-dilution line connected fluidly to the venous line, a tube pump tract, in the form of an open ring and predisposed in the supply line for coupling with a replacement liquid fluid circulation line, and an expansion chamber predisposed in the extracorporeal blood circuit and fluidly connected to the predilution branch and the post-dilution branch.
An apparatus made in this way is known, for example, in US 2005/0131331, which describes a medical fluid circuit unit for a hemodiafiltration treatment comprising: a fluid transport line having an inlet end predisposed for removable connection with an on-line preparation circuit of a dialysis fluid; a pump tract predisposed for coupling with a peristaltic pump for dialysis fluid circulation; an ultrafilter fluidly inserted in the transport line for the dialysis fluid ultrafiltration with the aim of making it suitable for infusion in an extracorporeal blood circuit as a replacement fluid; and a bifurcation in which the transport line divides downstream of the ultrafilter in a pre-dilution line, connected to the blood circuit upstream of a hemodiafilter, and a post-dilution line, connected to the blood circuit downstream of the hemodiafilter.
Italian patent IT 1222122 illustrates, in FIG. 3, an integrated module for hemodiafiltration constituted: by a chamber 1 for pre-pump arterial pressure monitoring in which the blood coming from the patient enters, provided with an attachment 2 for monitoring the pressure, an attachment 3 for a service line, an attachment point 4 for connecting to the patient, and an attachment point 5 to the arterial pump tube tract; by an arterial post-pump expansion chamber 6, connected to the pre-pump chamber by the pump tube, external of the module and subjected to the action of the arterial blood pump, and from which the blood is sent to the hemodiafilter, provided with an attachment point 7 for the arterial pump tube tract, an attachment 3 for a service line, an anticoagulant infusion point 8 and an attachment point 9 for connection with the dialyser; by a monitoring chamber 10 of the venous pressure, to which the purified blood from the hemodiafilter and a replacement fluid flow, the monitoring chamber 10 being provided with a filter 11, an attachment for a service line, an attachment point 12 of the connection in exit from the dialyser, an attachment point 13 for connection with the replacement fluid infusion, and an attachment point 20 for the infusion pump tube; by a control chamber 17 of the replacement fluid coming from one or more bags and connected to the venous chamber 10 by a pump tube subjected to the action of a peristaltic pump, provided with an attachment 3 for a service line, an attachment point 18 of the connection with the replacement bag solution, and an attachment point 19 for the infusion pump tube tract. The integrated module can be made of any thermoplastic material suitable for use in the biomedical field for contact with blood, either rigid or semi-rigid, for example polyvinyl chloride, polycarbonates etc.
U.S. Pat. No. 4,666,598 describes an extracorporeal blood circuit provided with: a cartridge including an arterial blood chamber and a venous blood chamber; a first arterial branch having a flexible tube with a first end designed for connection with a vascular access of a patient and with a second end to connected to an inlet of the arterial chamber; a pump tract formed by a flexible ring-shaped tube which extends from one side of the cartridge and has a first end connected to an outlet of the arterial chamber and a second end connected to a blood passage conduit internal of the cartridge; a second arterial branch having a flexible tube with a first end connected to the blood passage conduit and a second end designed for connection to an inlet of a membrane blood treatment device (dialyser); a first venous branch having a flexible tube with a first end designed for connection with the membrane blood treatment device and with a second end connected to an inlet of the venous chamber; a second venous branch having a flexible tube with a first end connected to an outlet of the venous chamber and a second end designed for connection to the vascular access of the patient. The cartridge exhibits three projections for mounting to the front panel of a dialysis machine, in which two projections are formed by two tubular extensions with parallel axes, arranged one above the other on a side of the cartridge adjacent to the arterial chamber, and a third projection arranged on the opposite side of the cartridge, adjacent to the venous chamber. The cartridge is placed in a work configuration by coupling each projection with a respective clip, arranged on the panel of the dialysis machine.
U.S. Pat. No. 5,441,636 describes an integrated blood treatment module comprising a support element in the form of a quadrilateral plate bearing on each side thereof four open-ring shaped pump tracts, projecting towards the outside of the periphery of the support element and designed for coupling with respective peristaltic pumps, and a device for membrane blood treatment (dialyser) fixed to the centre of the support element and having a blood chamber, fluidly connected to a pump tract for blood circulation, a fluid chamber fluidly connected to a pump tract for circulation of fresh dialysis liquid and a pump tract for circulation of exhausted dialysis liquid, and a semipermeable membrane which separates the blood chamber from the fluid chamber. The support element is mounted on a blood treatment apparatus by means of four elastic engagement fingers which extend from the front panel of the apparatus and which snap into openings afforded in the support element at opposite sides of the membrane blood treatment device.
WO 2004/004807 describes a circuit for infusion of a medical fluid in an extracorporeal blood circuit, comprising: a fluid transport line connected with a bag of medical fluid to be infused into the extracorporeal blood circuit; a flat support element having two tubular extensions to which the two ends of an open-ring pump tract are connected, the pump tract being predisposed for coupling with a peristaltic pump for circulation of the medical fluid; and a double-membrane air separator arranged fluidly downstream of the pump tract and integrated with the support element. The air separator comprises a hydrophilic membrane which holds back the gaseous component of the medical fluid and a hydrophobic membrane arranged in a breather for evacuation of the gaseous component. The support element exhibits at the centre thereof a through-opening which is used for mounting the element on a panel of a medical apparatus provided with the peristaltic pump.
Italian patent IT 1276447 describes a blood line which forms an integrated unit comprising an arterial line and a venous line connected to one another at a drip chamber belonging to the venous line. The drip chamber is formed by a container that is superiorly closed by a cap. A through-hole is afforded internally of the cap, which through-hole belongs to the arterial line and exhibits at the ends thereof connections for tracts of tube of the arterial line. One of these connections is fixed at an end of an arterial pump tract, the other end of which is fixed to a connection and support element which is fixed to the outside of the container and which is further connected fluidly to a patient tract of the arterial line.
U.S. Pat. No. 4,436,620 describes an integral hydraulic circuit for a hemodialysis apparatus which comprises a rigid and flat cartridge which defines three blood chambers constituted by a pre-pump arterial blood chamber, a post-pump arterial blood chamber, and a venous chamber. The cartridge further defines two tubular extensions for coupling the arterial pump tract which fluidly connects the pre-pump chamber with the post-pump chamber, and gripping organs for engaging a dialyser connected fluidly to the blood flow line.
WO 2005/044341 describes an integrated blood treatment module comprising a blood treatment device in the form of a hollow fibre filter provided with a tubular housing rigidly connected with two tubular extensions to which the ends of a pump tract for a peristaltic pump are coupled. The module further comprises a venous chamber for air/blood separation.
US 2005/0230292 describes a hemodialysis cartridge with an integrated dialyser, in which the cartridge comprises a rigid base body affording various recesses which are covered by an elastomer sheet. These recesses, in collaboration with the elastomer covering sheet, define blood passages, an arterial measuring chamber, and two blood pumping chambers. The cartridge is coupled to a hemodialysis machine provided with various actuators and sensors which interact with the elastomer sheet.
One of the problems in the prior art is that of providing a disposable fluid circuit which is usable for performing a hemo(dia)filtration treatment with pre-dilution and/or post-dilution and which is couplable simply, rapidly, economically and reliably to a machine for monitoring the treatment.